1. Field of the Invention
This invention relates to trigger sprayers of the type which are mounted on the top of a container. Such sprayers comprise a trigger-operated pump which pumps liquid, such as a cleaner, up through a dip tube out of the container to discharge through an appropriate orifice. More specifically, this invention relates to a trigger sprayer in which the pump is a bellows worked by the trigger. The invention further relates to vent means for permitting air to pass from the outside into the container to take the place of the removed liquid and equalize internal air pressure with the outside.
2. Description of Related Art including Information Disclosed under .sctn..sctn.1.97 to 1.99
The prior art includes a large number of trigger sprayers in which the pump means is a bellows. A number of these references provide hinged triggers, each having a leg which engages and works a bellows pump when the trigger is pulled. Examples are the U.S. Pat. No. 3,986,644 which issued Oct. 19, 1976 to Grogan et al; U.S. Pat. No. 4,138,038 which issued Feb. 6, 1979 to Grogan; U.S. Pat. No. 4,155,487 which issued May 22, 1979 to Blake; and U.S. Pat. No. 4,204,614 which issued May 27, 1980 to Reeve.
The need for appropriate venting means to permit the passage of air from the outside to the inside of the container is also the subject of patents, a number of which are in the name of Tetsua Tada. In Tada U.S. Pat. No. 3,897,006, for instance, a probe moves toward the container as the trigger is pulled and pokes open a rubber sealing sleeve in a section of the sprayer housing. Other showings of venting include Smith et al U.S. Pat. No. 3,973,700 wherein a vent passage extends from the container up into the sprayer housing and ends in an opening to the atmosphere. The opening is closed off when the trigger is in retracted position.
Prior art includes showing of triggers which are hinged to a housing by means of a "living" hinge. See, for instance, U.S. Pat. No. 4,199,083 which issued Apr. 22, 1980 to LoMaglio. Also in the past, doors for sealing the sprayer orifice have hinged to the front of the sprayer housing as shown in the Tada U.S. Pat. No. 4,230,277.